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The bird family tree just gained a new and distinctive member, according to Chinese paleontologists.

They have found a long-legged, toothy, stubby-armed, three-fingered dinosaur that was an important early member of the lineage that includes birds and their closest dino relatives.

The 160-million-year-old dinosaur, Haplocheirus sollers, is about 10 million years older than what is believed to be the world's first known bird, Archaeopteryx, and exhibits characteristics associated with both dinos and birds.

As a result, the new species helps to fill in the fossil record and cement the long-held view that birds did indeed emerge out of the Maniraptora "hand snatcher" clade.

"Many dinosaurs are very birdlike and early birds are dinosaurlike," co-author Xing Xu told Discovery News, adding that there is still debate over the exact moment when birds first emerged.

"It is more or less depending on what you call a bird a bird, which is somewhat an arbitrary procedure," said Xu, a professor in the Institute of Vertebrate Paleontology & Paleoanthropology at the Chinese Academy of Sciences. "For example, Epidexipteryx (a small, feathered "dinosaur") could be considered to be the earliest representative of the avian lineage."

For the study, published in the latest issue of Science, Xu and his colleagues analyzed the new dinosaur, discovered in orange mudstone beds at Junggar Basin in Xinjiang, China. According to Xu, the researchers determined it was "a relatively small carnivorous dinosaur" about 6.5 feet long with a slender head and "numerous small teeth."

10 mind-bending dino discoveriesThe "hand snatcher" description seems quite appropriate in this case, since the dinosaur's hands had three strong fingers, with the middle finger being "much more robust than the others."

H. sollers belonged to the Alvarezsauroidea group of dinosaurs, now thought to have originated in Asia. Later members possessed a single, massive claw on each hand that was probably used for digging. The impressive middle finger on the new dinosaur likely represented an early evolutionary stage for this claw.

The new dinosaur, which was big for a bird but small for a dino, also shows how some dinosaurs shrunk down to bird size over time.

H. sollers is the world's largest and oldest known alvarezsauroid — 63 million years older than other known members of this group.

"We now know that feathers came before wings, so feathers did not originate as flight structures," said Mike Benton, a professor of paleontology at the University of Bristol who worked on the Nature study. "We therefore suggest that feathers first arose as agents for color display and only later in their evolutionary history did they become useful for flight and insulation."

By analyzing color-bearing organelles buried in the fossils of bird-like dinosaurs and early birds, Benton and his team were even able to reconstruct the color of these prehistoric animals. The dinosaur Sinosauropteryx, for example, sported orange and white rings down its tail. The early bird Confuciusornis, on the other hand, had patches of white, black and orange-brown coloring.

"These discoveries open up a whole new area of research," said Benton, "allowing us to explore aspects of the life and behavior of dinosaurs and early birds that lived over 100 million years ago."